Exidor's Logic Puzzle Place

Here are old puzzles.

Puzzle 1

Weighing marbles

Given are 12 marbles. One of these marbles is slightly heavier or lighter than the others. You have a two plate scale. You are allowed to weigh three times.Can you find the marble that differs in weight?

Puzzle 2

The man with the hat

There are four man standing in front of a firing-squad. Two of them (nr.1 & 3) wear a black hat and two of them (nr.2 & 4) wear a white hat. They are all facing the same direction and between nr.3 and nr.4 stands a brick wall (see picture). So nr.1 can see nr.2 & 3, nr.2 sees nr.3, nr.3 sees only the wall and nr.4 doesn't see a thing. The men know that there are two white and two black hats. The commander of the firing-squad is willing to let the men go if one of them can say what color hat he is wearing. The men are not allowed to talk. The only thing they may say is "I'm wearing a white/black hat". If one of the men knows which hat he is wearing he must tell it and all men will be free.Which man knows 100% sure what color hat he's wearing?

=>I I I | I1 2 3 4

Puzzle 3

Farmers problem

A farmer is standing on one side of the river and with him are a wolf, a goat and a box with cabbages. In the river there is a small boat. The farmer wants to cross the river with all the three items who are with him. There are no bridges and in the boat there is only room for the farmer and one item. But if he leaves the goat with the cabbages alone on one side of the river the goat will eat the cabbages. If he leaves the wolf and the goat on one side the wolf will eat the goat. Only the farmer can seperate the wolf from the goat and the goat from the cabbage.

How can the farmer cross the river with all three items, without one eating the other ?

Puzzle 4

Lost

You are lost in a forest. The forest is between two villages. In villageA live only liars, they always lie. In village B people always tell the truth. You want to go to village B. Then you see a man from village A or B. You can ask him only one question.Which question will you ask him to know for sure where village B is ?

Puzzle 5

Meat purchase

A butcher goes to the market with $100 cash. He has to buy exactly 100 animals. There are cows, geese and chicken for sale.A cow costs $15, a goose is $1 and a chicken costs $0.25. He has to buy at least one of each animal and has to spend all his money.

What does the butcher buy?

Puzzle 6

Don't hang yourself

A fool wants to tie a rope around the earth. So he buys a rope of 40,000 KM and ties it around the world. His neighbour, also a fool, wants to do the same only he wants the rope on sticks 1 meter above the ground.

How much more rope does he need?And how much more rope do you need when you use a tennis ball instead of the earth?

Puzzle 7

Mother and daughter

A mother is four times as old as her daughter. In 20 years she will be twice as old as her daughter.

How old are mother and daughter now?

Puzzle 8

What a rip-off

Achmed and Ali are camel-drivers and on one day they decided to quit their job. They wanted to become shepherds. So they went to the market and sold all their camels. The amount of money(dinars) they received for each camel is the same as the total of camels they owned. For that money they bought as many sheep as possible at 10 dinars a sheep. For the money that was left they bought a goat.On their way home they got in a fight and decided to split up. When they divided the sheep there was one sheep left. So Ali said to Achmed "I take the last sheep and you can get the goat". "That's not fair" said Achmed, "a goat costs lesser than a sheep". "Ok", Ali said "then I will give you one of my dogs and then we are even". And Achmed agreed.

What costs a dog?

Puzzle 9

West Wessex Marathon Race (by Martin Hollis)

With a field of five for the west wessex marathon race, there was littleto interest the bettors. So, Peter Piper opened one of his ingeneousbooks where he accepts multiple bets at high odds. To place a multiplebet, you must bet on two propositions, and you will win only if you arewholly successful. Peter Piper is now on an extended vacation because ofthe bettors who lost these bets:

1) A will not win the gold, nor B the silver.2) C will win a medal, and D will not.3) D and E will both win medals.4) D will not win the silver, nor E the bronze.5) A will win a medal, and C will not.

Who won which of the medals?

Puzzle 10

Bar puzzle (sent by Dan Ambroise)

Five people visit a bar for a drink of Scotch Whisky. They allhave their drink served differently and by different bar staff. Fromthe clues given below, can you work out which bar person served whom,how they had their Scotch and in what order they were served at thebar.

Someoneis served a Scotch & Cola by Carmen. Mrs Johnsonwas not served her Scotch & Ginger Ale by Marcella. Mr Weisswas served by Paul. The personwho drinks Scotch & Cola wasn't served second. The cocktaildrinker was served last. Marcella served the fourth person in line but they didn't order a Scotch& Soda. NeitherCarmen nor Hans served Mr Petit who was third in line at the bar. Firstin line was not Miss La Rue.

Puzzle 11

U2 puzzle

U2 has a concert that starts in 17 minutes and they must all cross abridge to get there. All four men begin on the same side of the bridge.You must help them across to the other side. It is night. There is oneflashlight. A maximum of two people can cross at one time. Any party who crosses, either 1 or 2 people, must have the flashlight with them. The flashlight must be walked back and forth, it cannot be thrown, etc. Each band member walks at a different speed. A pair must walk together at the rate of the slower man's pace:Bono:- 1 minute to crossEdge:- 2 minutes to crossAdam:- 5 minutes to crossLarry:- 10 minutes to crossFor example: if Bono and Larry walk across first, 10 minutes have elapsedwhen they get to the other side of the bridge. If Larry then returns withthe flashlight, a total of 20 minutes have passed and you have failed themission.

Can you get them across in 17 minutes?

Puzzle 12

Who own's the zebra?

There are five different houses.Each house has its own color.Each house has a man of a different nationality.Each man drinks a different drink.Each man has a differnt pet.Each man smokes a different cigarette.

The Englishmen lives in the red house.The Swede has a dog.The Dane drinks tea.The Green house is on the left side of the white house.The man in the green house drinks coffee.The man that smokes Pall Mall has birds.The man in the yellow house smokes Dunhills.The man in the middle house drinks milk.The Norwegian lives in the first house.The man that smokes Blends lives in the house next to the house withcats.The man in the house next to the house with the horse, smokes Dunhills.The man who smokes Blue Masters drinks beer.The German smokes Princes.The Norwegian lives next to the blue house.Water is drank in the house next to the house where Blends are smoked.

Puzzle 14

Another marble puzzle (thanks to Matt in the UK)

You have fifty bags, each with approximately one hundred balls inside.You have a weighing machine with a digital readout, with 3 places ofdecimals on the display, calibrated in grams, it is capable of weighing aninfinite amount (but it won't have to).All of the balls in all of the bags weigh 1 gram, except in one bag in whichall of the balls weigh 1.001 grams.You cannot tell by look or feel which bag has the heavier balls.

How do you determine which bag contains the heavier balls? You can use theweighing machine only once (which means you can obtain only one reading fromit before it self destructs).

Puzzle 15

Good bargain (thanks to Opie Cooper)

Two strangers from different parts of America both build simular apartment buildings in their home towns. By chance, they both forget an important part of thier project. They each, once again by chance, call the same national hardware store and order the missing items. The prices they are quoted are as follows:

one will cost them $2.two will cost them $2.twelve will cost them $4. and a hundred and fourty-four will cost $6.

What was the item they needed?

Puzzle 16

Grain silos

Three grainsilos have the following capacity:

A 8000 kilosB 5000 kilosC 3000 kilos

A is full, B and C are empty.

Can you without weighing put 4000 kilos in silo A and 4000 kilos in siloB?

Puzzle 17

Big Ben

A clock strikes '6' in 5 seconds.

How long does it take to strike '12'?

Puzzle 18

Who took the candy bar? (thanks to Nils Robertson)

During the lunch hour at school, a group of five boys from Miss Jones home room visited a nearby lunch wagon. one of the five boys took a candy bar without paying for it. When the boys were questioned by the school principal, they made the following statements in respective order:1. Rex: "Neither Earl nor I did it."

2. Jack: "It was Rex or Abe."

3. Abe: "Both Rex and Jack are lying."

4. Dan: "Abe's statement is not true; one of them is lying and the other is speaking the truth."

5. Earl: "What Dan said is wrong."

When Miss Jones was consulted, she said, "Three of these boys are always truthful, but everything that two of them say will be a lie."Assuming that Miss Jones is correct, can you determine who took the candy bar?